1. Field of the Invention
The present invention generally relates to control of aircraft from flight origination to destination, and more particularly to a collaborative system for scheduling arrivals at destination airports.
2. Background Description
It would not be unfair to say that the most accurate way to describe the general process of arrival management at airfields adheres to a principal of first come first served. The use of this simple method of ordering traffic into a landing pattern is quite adequate when the required capacity to land aircraft is never exceeded by the number of aircraft that at any particular time of day arrive and ask to land.
Unfortunately the latter situation of a capacity which is exceeded at particular times by the number of aircraft which arrive and ask to land is already common and will only become more so as demand for air travel increases and the solution of building additional runways is unacceptable. In reaction to the situation of excess demand airfields will apply a slot process which will crudely limit the number of aircraft planned to fly to the airfield. However this slot will still not have a direct connection with what time the slotted aircraft will be sequenced to land.
Given the current lack of relationship between any slot or the flight""s scheduled arrival time (time table) and the time the flight may be landed (i.e. instructed to commence its approach into the destination airfield) the current behaviour of a flight will tend to follow the following pattern: airlines will continue to focus considerable resources at achieving on time departures (in accordance with the time table); the flight from that point onwards is conducted to take every advantage of any opportunity to save time that is considered safe and prudent by the Captain and crew. This pattern can manifest itself as direct routings, increased decent and cruise speeds, and the like. The point to note is that until the aircraft is told by air traffic control (ATC) at the destination airfield that it is commencing its approach it has no idea when it will actually land.
The activity connected with saving time en route has as its purpose getting into the queue to land as soon as possiblexe2x80x94not landing itself. It is a curiosity of both the system and the way that punctuality is sold to passengers that considerable resources are currently focused on an on time departure at Standard Time of Departure (STD), but without any clear process for managing the arrival and landing time with comparable certainty. The direct consequence of this is that the arrival process at congested airfields is inefficient for both ATC agencies and airlines.
The consequence of the current system for airlines is that economic and operational inefficiencies are part of normal business. Firstly, time tables provide additional time, beyond actual flight and taxi times required, to allow for delays either airborne or pre-departure. This is known as padding of block times, and produces additional cost because more aircraft are required to cover the same number of services. Secondly, on the day of operation, crew will uplift additional fuel to allow for holding time in the air, be it created by the lengthening of the route by ATCxe2x80x94(lateral holding) or xe2x80x9crace trackxe2x80x9d holding over a navigational fix. This creates cost to the airlines in three ways: 1) if you carry additional weight of fuel the aircraft burns additional fuel to carry it; 2) when you are in a holding pattern you burn additional fuel and incur engineering costs for the time airborne; and 3) if the anticipated holding does not occur, although the airline may have a portion of the residual excess fuel left in the aircraft for the next aircraft sector, it will suffer a cost differential as this fuel will inevitably be more expensive than fuel purchased at the carrier""s home airport. In addition, in certain countries the inefficiency described has been recognised as having a level of environmental impact which could be avoided.
For ATC agencies the above described process results in an unmetered and unsorted flow of aircraft that is not matched to any optimal sequence for landing. This will inevitably result in higher workloads for controllers and can adversely affect safety if aircraft arrive in significant bunches. Also, because of the xe2x80x9cfirst come first servedxe2x80x9d precedent, controllers are obliged to sequence aircraft in a way that inevitably will be inefficient. In summary the current lack of a process that manages the overall flight process is significantly inefficient for all stakeholders in the ATC system.
The aviation industry already recognises that there is a problem to be solved in this area and solutions are being sought. The significant characteristic of all these approaches is that landing slot timing is determined after departure. All current and substantially developed proposed systems who describe themselves as arrival management tools are concerned with sequencing aircraft that are already airborne and in relatively close proximity to the destination airfield (usually within the radar horizon). Some systems only look at aircraft that are already in airborne holding patterns near the airfield and then sequence them as far as the xe2x80x9cfirst come first servedxe2x80x9d rule will allow. ATC concepts have always looked at how to order the aircraft once in flight on the basis that they will appear in the ATC control zone at the destination airport in a largely random manner. The randomness of the entry of aircraft has always been seen as the ultimate problem. In short, the focus of these systems is to respond as efficiently as possible to the mix of traffic that arrives in the vicinity of the destination airport, by de-bunching and tinkering with the order.
Those systems that intervene in the approach of aircraft before they have reached a race track holding pattern near an airfield do effectively delay the aircraft""s approach through lengthening the distance flown. Satellite based information systems can further refine this approach and better enable an airfield ATC to sequence landings. Although this is more cost efficient than racetrack holding it is still far from optimal for the airline. This method is typically used in the United States. Where arrival management tools are applied to the aircraft in the holding stacks the effect is to marginally reduce the time spent holding. Although this confers some level of benefit it still fails to address the inefficiency of building in additional time at the departure end of the flight.
The inadequacies of current and projected approaches to arrival management are encapsulated by their philosophical stance of xe2x80x9cdoing something to the aircraftxe2x80x9d once they are in flight rather than effecting a joint plan before the aircraft departs, where both the ATC agency and the aircraft crew then work toward that plan. As a consequence of this post-departure approach to arrival management there is no opportunity or reason for change in the behaviours of airlines in the conduct of their flights, and also no potential to capture the operational savings on fuel/engineering or better resource management (aircraft utilisation, ground resources and airport stands).
It is therefore an object of the present invention to provide arrival landing slots (Tactical Arrival Times or xe2x80x9cTATsxe2x80x9d) at the destination airport prior to departure.
It is also an object of the invention to optimize use of the landing capacity at crowded airports.
An object of the invention is to reduce the ATC resources currently expended to respond efficiently to random arrival of aircraft in the ATC control space.
It is another object of the invention to capture operational savings on fuel, engineering services, and improved management of aircraft, ground resources and airport stands.
It is a further object of the invention to provide airlines with means and incentives to optimize the establishment and execution of their flight schedules.
Another object of the invention is to minimize airborne delays, which are built into the difference between gate departure and gate arrival times.
A further object of the invention is to stabilise entry of arriving aircraft into the ATC process.
It is also an object of the invention to provide a stable platform upon which further xe2x80x9cgate to gatexe2x80x9d refinements can be built.
Another object of the invention is to provide a stable platform of cost and scheduling benefits for users, a platform which will serve as a driver for the airlines which are users of the invention to change their behaviours and practices.
The present invention provides a Schedule Activated Management System (SAMS) to manage the inbound flow of aircraft to an airfield by ensuring that aircraft are pre-sequenced (i.e. before departure) into a uniquely developed arrival stream.
The SAMS process uses operational data derived from airlines and then provides a collaborative methodology for sharing this data with the air traffic control (ATC) agency in such a manner as to negotiate for each flight a Tactical Arrival Time (TAT). The outcome of this collaborative negotiation is a daily arrival schedule providing a predetermined operational arrival time for each aircraft movement. The data used in the SAMS system relates to airline punctuality, taxi times at departure airfields and actual flight times predicted on a flight-by-flight basis by airline flight planning systems. This information is combined to effect a predictive arrival time at a desired navigational fix. When used in conjunction with an optimised sequencing process for the final arrival time, the system then creates a TAT for an individual flight. Furthermore, although TATs will be issued prior to departure for all aircraft at a SAMS compliant airport, the system can also incorporate tactical updates to the TATs via ground to aircraft data or voice communications. A pre-departure only version would be considered a xe2x80x9cbasic SAMS system.xe2x80x9d With the development and incorporation of a tactical update module the system would be considered an xe2x80x9cadvanced SAMS systemxe2x80x9d.
Arrival delays are highly predictable through effective modeling. Furthermore, the entry of aircraft into the ATC process is stabilised by agreeing on a TAT and consequently agreeing on a fixed departure time. This combination of a TAT issued prior to departure and a fixed departure time is novel. In the past users of the ATC system have not been involved in this form of collaborative management processxe2x80x94in effect a joint decision between the airline users and the ATC.
The method of the invention optimizes aircraft arrivals at congested airports by obtaining basic flight information for all flights scheduled to arrive at an airport during a specified operational period, this information including for each flight a flight number and a requested Tactical Arrival Time (TAT); creating from this basic flight information target TATs for each flight; offering these target TATs to the airlines controlling these flights; negotiating with the airlines until there is acceptance of TATs for these flights; and then issuing final TATs, each TAT for a flight being issued prior to departure of the flight. Airlines share proportionally in a measure of departures from requested TATs, such measures being optionally weighted.